Description of short int, long, float, and double usage Problems

Short int short integer two byte value range-32768 ~ 32767
The value range of four long integer bytes is-2147483648 ~ 2147483647 float single precision 4 byte value range-3.4*10 (-38 )~ 3.4*10 (38)
Double double 8-byte value range-1.7*10 (-308 )~ 1.7*10 (308)

This problem occurs when access data is exported to DBF. The field width in DBF is not the number of bytes occupied by access fields, but the number of characters. In DBF, integers and floating-point numbers are stored as characters. For example,-3.134 is stored as "-3.135", which contains 6 characters.
So
For short integers in access, the field width stored in DBF is 6;
For long integers in access, the field width stored in DBF is 11;
For the single precision in access, the field width in DBF is 18, and the decimal point is 7;
For the Double Precision in access, the field width in DBF is stored as 24, and the decimal point is 15.
That is to say, it is difficult to ensure the accuracy of Single-precision and double-precision data in access to be transferred to DBF.